Does anyone even, like, own rules??

[Anaraxes]

Originally Posted by RyanW

Recipes may fall under trade secrets.

True. But trade secrets have no IP protection. That is, they're secret. If the secret gets out, too bad. So that's a different category than copyright / trademark / patent.

As you point out, it's an irrelevant category for games, as you kind of have to tell people what the rules are for them to be useful. Though there's always that one GM that insists on just doing it all his own mysterious way...

My intended point was merely that if you wanted to protect game mechanics, you could. It's not copyright or nothing. Only a few cases that I know of have done so (Magic: the Gathering, Scrabble, Monopoly...), but it's possible. Also read that some video games have patented mechanics.

Which possibility raises the specter of "defensive patents" for game companies. If owners of D&D never patented those mechanics, then theoretically Paizo (say) could try to patent those used in Pathfinder. And then possibly turn around and sue D&D for using their patented mechanics like "roll d20 plus modifiers over AC to hit". We can of course hope such a lawsuit would fail due to D&D itself being prior art and differences between editions (say, THAC0 or inverting the AC scale) counted as obvious to a practitioner of the art of game design. But we'd only know after an actual court case. So for safety, a lot of companies just patent everything they do just in case, with no intent to use those patents against anyone else, but rather fend off the reverse. That kind of legal expense would be another burden on RPG companies with tiny revenue. So it could just as well to declare the mechanics as open and at least collect the goodwill that might bring.